Organizers of the America's Cup challenger series reluctantly agreed to resume racing in Auckland this weekend but expressed frustration the event will face coronavirus-related crowd restrictions.

The challenger series, also known as the Prada Cup, was temporarily suspended this week as the host city imposed a snap three-day lockdown to contain a virus outbreak.

With the flare-up under control, stay-at-home orders were lifted late Wednesday and organizer America's Cup Events (ACE) said the race-off between Luna Rossa of Italy and Ineos Team UK would resume on Saturday.

Luna Rossa leads 4-0 in the best-of-13 regatta, which will determine which boat challenges Team New Zealand for the America's Cup proper next month.

In an unusual move, ACE Chairwoman Tina Symmans said she would have preferred to delay the event further until Auckland lifted COVID-19 restrictions limiting crowd numbers to 100.

But she said Luna Rossa had insisted the teams get back on the water and questioned the Italians' sportsmanship, saying it was in no one's best interest to race in front of limited crowds.

"It's clear that their focus is solely on Luna Rossa taking the Prada Cup, rather than the greater good of the country who have worked so hard in ­order to be in a position to stage this event," she said.

Luna Rossa spokesman Francesco Longanesi Cattani shrugged off Symmans' criticism, saying the team simply wanted to follow the rules that had been agreed to by all participants before the event began. "This is what we're doing and what we want to implement," he told reporters.

Ineos Team UK, led by British sailing legend Ben Ainslie, said it would have supported delaying racing for up to a week so it could take place in front of unlimited crowds.